package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import cn.hutool.core.util.BooleanUtil;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.core.script.RedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock {
    private String name; //业务名称
    private StringRedisTemplate stringRedisTemplate;

    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    private static final String KEY_PREFIX = "lock:"; //锁的前缀
    private static final String ID_PREFIX = UUID.randomUUID().toString(true) + "-"; //线程标识的前缀
    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT; // 读取lua脚本

    static {
        UNLOCK_SCRIPT=new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }

    @Override
    public boolean tryLock(long timeoutSec) {
        //获取线程标识
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        //获取锁
        Boolean isLock = stringRedisTemplate.opsForValue()
                .setIfAbsent(KEY_PREFIX + name, threadId, timeoutSec, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(isLock);
    }

    @Override
    public void unlock() {
        //调用lua脚本
        stringRedisTemplate.execute(
                UNLOCK_SCRIPT, //lua脚本
                Collections.singletonList(KEY_PREFIX + name), //key类型参数KEYS[]
                ID_PREFIX+ Thread.currentThread().getId()); //其他参数ARGV[]
    }

    /*@Override
    public void unlock() {
        //获取线程标识
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        //获取锁中的标识
        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
        //判断标识是否一致
        if(threadId.equals(id)){
            //一致，释放锁
            stringRedisTemplate.delete(KEY_PREFIX + name);
        }
        //反之不做处理（由于业务阻塞，锁已经提前释放）
    }*/
}
